1. Field of the Invention
The present invention relates to an acoustic sensor, and in particular, to an acoustic sensor for use with a hearing prosthesis.
2. Related Art
Implantable hearing prostheses are used to provide therapy to individuals suffering from hearing loss.
Hearing prostheses, such as conventional hearing aids and more recently cochlear implants, have traditionally been required to perform two distinct functions, namely the detection and processing of ambient sound into a processed signal, and the use of the processed signal to generate a stimulus for delivery to the auditory system.
In implantable systems such as cochlear implants and implantable hearing aids, these functions are typically performed by separate parts of the systems. The detection and processing of speech and ambient sound typically occurs in the external part and includes a microphone for sensing the speech and ambient sounds and a processing unit for processing the speech and ambient sounds into a signal to be transmitted to the implanted section. The delivery of the processed signal to the auditory system typically occurs in the internal or implanted part of the system, whereby the processed signal is received by an implanted stimulator unit which decodes the processed signal and delivers the appropriate stimulation, via intracochlear electrodes or electromechanical stimulation, to the auditory pathway to provide the recipient with a perception of the speech and ambient sounds.
As a result, a common aspect of conventional hearing prostheses has been the need for the recipient to carry or wear the external part of the system in a manner which ensures that there is constant communication between the external part and the implanted part. The constant presence of the external part of the system can greatly restrict the type of activities the recipient can perform whilst using the prosthesis. For example, water based activities such as swimming, showering or even exposure to rain, have traditionally not been recommended due to potential damage to the external part. Further to this, the visual presence of the external part can result in a degree of embarrassment to the wearer, especially for children, where a degree of social stigma may still exist.
It is for these reasons that totally implantable hearing prosthesis systems have been proposed. Such systems provide all components of the prosthesis implanted within the recipient, resulting in a prosthesis that is invisible to the casual onlooker.
However, in order to provide a totally implanted hearing prosthesis system, there is a need to provide an acoustic sensor that can be implanted within the recipient, and which is still capable of detecting speech and ambient sounds with a high degree of precision.